Java-Klasse "List", wer kann mir helfen?

public class List{

private Element first;
private Element current;
private Element last;
private Element Element;


public List(){
first = null;
current = null;
last = null;
}

public boolean isEmpty(){
if ( first == null ){
return true;
}
}
public boolean hasAccess(){
if ( current == null ){
return false;
}
}

public void next(){
if ( first != null && current != null && last != current) {
current = Element.getNext();
}
}
public void toFirst(){
current = first;
}
public void toLast(){
current = last;
}
public Object getObject(){
if (current == null) {
return (null);
}else{
return (current);
}
}
public void setObject(Object pObject){
if (current != null && pObject != null){
current = first;
}
}
public void append(Object pObject){


}
public void insert(Object pObject){


}
public void concat(List pList){


}
public void remove(){


}

}

public class Element {

// Anfang Attribute
private Element pre;
private Object inhalt;
private Element next;
// Ende Attribute


public Element(Object pObject) {
pre = null;
inhalt = pObject;
next = null;
}

// Anfang Methoden

public void setPrevious(Element pElement) {
pre = pElement;
}

public Element getPrevious() {
return pre;
}

public void setInhalt(Object pObject) {
inhalt = pObject;
}

public Object getInhalt() {
return inhalt;
}

public void setNext(Element pElement) {
next = pElement;
}

public Element getNext() {
return next;
}
// Ende Methoden
}